▎ 摘　　要

NOVELTY - Two-dimensional covalent organic framework comprises a regularly porous, covalently linked and layered structure, where the dielectric constant k is less than 2.4. USE - The two-dimensional covalent organic framework is used in a heterostructure, a dielectric bilayer and a capacitor, and for preparing a two-dimensional covalent organic framework thin film (claimed). ADVANTAGE - The framework possess high thermal conductivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) (1) a heterostructure comprising the two-dimensional covalent organic framework and a templating substrate; (2) (2) a dielectric bilayer comprising the two-dimensional covalent organic framework and a blocking layer configured to minimize leakage current; (3) (3) a capacitor comprising the two-dimensional covalent organic framework positioned between two conductive plates; and (4) (4) a method for preparing two-dimensional covalent organic framework thin film, involving (a) contacting a solution with a templating substrate in a reaction vessel under conditions sufficient for preparing a covalent organic framework, where the heterostructure comprises a first layer of two-dimensional covalent organic framework deposited on the templating substrate and a liquid phase is formed within the reaction vessel, and (b) removing an insoluble covalent organic framework dispersed within the liquid phase, where the solution comprises building units, linking units, and a solvent.